The WBBL has traditionally been run in conjunction with the men's Big Bash season from December to February. The Sixers are the most successful club in WBBL history, having made three Big finals, winning the last two.
Cricket Australia CEO James Sutherland confirmed the move in an interview with Melbourne radio network SEN.
"In 2019-20 the women's T20 Big Bash League will move into the October-November period," Sutherland SEN said.
"It will be the primary cricket that is on through that period.
"The reason why it's not this year is because there is a World T20 event for the women in the Caribbean."